Major David Eastburn, a Pentagon spokesman, said the enlistment of transgender recruits will begin next month and proceed amid legal battles. The defence department also is doing a review, which is expected to carry into 2018.

Transgender individuals receiving hormone therapy must be stable on their medication for 18 months.

The requirements make it challenging for a transgender recruit to pass. But they mirror concerns President Barack Obama's administration laid out when the Pentagon initially lifted its ban on transgender service last year.